opencv显示大图--利用鼠标在固定窗口内显示大图

opencv显示大图–利用鼠标在固定窗口内显示大图

#pragma execution_character_set("utf-8")
#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv;
using namespace std;

Mat test = imread("test.jpg"); //测试图像

void on_mouse(int event, int x, int y, int flags, void *userdata);

int main()
{
int window_w = 800;
int window_h = 800;

if (!test.data)
{
cout << "load image failed !" << endl;
return 0;
}

namedWindow("test", 1);
Mat temp = test(Rect(0, 0, window_w, window_h));
int udata[4] = { window_w, window_h, test.cols, test.rows };
setMouseCallback("test", on_mouse, udata);
imshow("test", temp);
moveWindow("test", 40, 40);

waitKey();
return 0;
}

void on_mouse(int event, int x, int y, int flags, void *userdata)
{
int *window_param = (int *)userdata;
static int start_x = 0;
static int start_y = 0;
int w = *window_param;
int h = *(window_param + 1);
int img_w = *(window_param + 2);
int img_h = *(window_param + 3);
static Point ld = Point(0, 0);
static Point ru = Point(0, 0);

if (event == EVENT_LBUTTONDOWN)
{
ld = Point(x, y);
}

if (event == CV_EVENT_LBUTTONUP)
{
ru = Point(x, y);
//cout << "origin:" << ld << endl;
//cout << "now:" << ru << endl;
start_x = (ld.x - ru.x) * 1 + start_x;
start_y = (ld.y - ru.y) * 1 + start_y;
start_x = start_x > (img_w - w - 1) ? (img_w - w - 1) : start_x < 0 ? 0 : start_x;
start_y = start_y >(img_h - h - 1) ? (img_h - h - 1) : start_y < 0 ? 0 : start_y;
//cout << start_x << endl;
//cout << start_y << endl;
Rect roi(start_x, start_y, w, h);
Mat temp = test(roi);
imshow("test", temp);
}
}